• The Korean Journal of Physiology and Pharmacology
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• v.23 no.2
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• pp.121-130
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• 2019

Glutamate toxicity-mediated mitochondrial dysfunction and neuronal cell death are involved in the pathogenesis of several neurodegenerative diseases as well as acute brain ischemia/stroke. In this study, we investigated the neuroprotective mechanism of dieckol (DEK), one of the phlorotannins isolated from the marine brown alga Ecklonia cava, against glutamate toxicity. Primary cortical neurons ($100{\mu}M$, 24 h) and HT22 neurons (5 mM, 12 h) were stimulated with glutamate to induce glutamate toxic condition. The results demonstrated that DEK treatment significantly increased cell viability in a dose-dependent manner ($1-50{\mu}M$) and recovered morphological deterioration in glutamate-stimulated neurons. In addition, DEK strongly attenuated intracellular reactive oxygen species (ROS) levels, mitochondrial overload of $Ca^{2+}$ and ROS, mitochondrial membrane potential (${\Delta}{\Psi}_m$) disruption, adenine triphosphate depletion. DEK showed free radical scavenging activity in the cell-free system. Furthermore, DEK enhanced protein expression of heme oxygenase-1 (HO-1), an important anti-oxidant enzyme, via the nuclear translocation of nuclear factor-like 2 (Nrf2). Taken together, we conclude that DEK exerts neuroprotective activities against glutamate toxicity through its direct free radical scavenging property and the Nrf-2/HO-1 pathway activation.

• Fisheries and Aquatic Sciences
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• v.22 no.5
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• pp.11.1-11.8
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• 2019

Background: In the present study, the skin-whitening effects of a marine-sourced mixture that includes a fucoidanrich extract of Undaria pinnatifida (UPEF), a phlorotannin-rich extract of Ecklonia cava (ECE), and glycosaminoglycans (GAGs) from sea squirt skin were investigated. Methods: The whitening effects of the mixture and its components were evaluated by measuring the inhibition of mushroom tyrosinase and melanin synthesis in alpha-melanocyte-stimulating hormone (${\alpha}$-MSH)-stimulated B16F10 melanoma cells. Results: Each component alone markedly inhibited mushroom tyrosinase in a dose-dependent manner, and in ${\alpha}$-MSH-stimulated B16F10 cells, they inhibited melanin synthesis and were cytotoxic. However, the whitening effects of UPEF, ECE, and GAGs in combination were greater than those of each component alone. A mixture in the ratio of 4:5:1 (UEG-451) showed the strongest activity without cytotoxicity. Further study suggested that UEG-451 inhibits ${\alpha}$-MSH-stimulated melanogenesis in B16F10 cells by downregulating tyrosinase and tyrosinase-related proteins, such as TRP-1 and TRP-2, via the inhibition of MITF expression. Conclusions: These results suggest that mixing the different components at optimum ratios might be an effective way to improve their bioactivities and reduce toxicity and that UEG-451 possesses strong whitening effects that could be used in the cosmetic industry.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.1
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• pp.111-117
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• 2021

The study was aimed at developing an alternative therapeutic agent against acne vulgaris, one of the most common skin diseases, to meet the continuing demand for new therapies. Acne vulgaris is often associated with the acne-causing bacteria such as Cutibacterium acnes. To investigate the safety of agents against acne vulgaris, we evaluated the potential antibacterial activities of edible seaweeds against C. acnes in Korea. Forty-one edible seaweeds, including the brown, green, and red varieties, were selected for the antibacterial test. In comparison with other seaweeds, 70% ethanolic extracts of brown seaweeds, such as Cladophora wrightiana var. minor, Eisenia bicyclis, Ecklonia cava, Ishige foliacea, Ishige okamurae, Sargassum filicinum, and Sargassum miyabei Yendo, exhibited potential antibacterial activity against C. acnes with minimum inhibitory concentrations ranging between 64 and 128 ㎍/mL. To investigate the active anti-acne agents and to enhance our understanding of the antibacterial activities against C. acnes, further solvent-fractionation experiments are warranted. The findings imply that brown seaweeds can be a potential source of natural agents against acne vulgaris.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.5
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• pp.691-700
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• 2023

This study examined the seasonal variations of subtidal marine algal community structures along four sites in Jejudo Island, Korea, from February 2016 to November 2018. A total of 147 marine algal species were identified, including 13 green (8.84%), 26 brown (17.69%), and 108 red algae (73.47%). During the study period, the number of species was highest in Sagye (116 species) followed by numbers in Sinheung (98 species), Bukchon (90 species) and Sinchang (73 species). Ecklonia cava, Peyssonnelia caulifera, Synarthrophyton chejuense, Corallina aberrans and Corallina crassisima occurred at all study sites and in all seasons. The average annual biomass of marine algal flora was 746.29±88.85 g wet wt./m² and ranged from 652.25 g/m² at Sinheung to 979.91 g/m² at Sagye. The brown alga E. cava was the most dominant species, occupying 42.85% (319.80 g/m²) of the total seaweed biomass. Subdominant species were C. crassissima and Undaria pinnatifida, comprising 10.22% (76.29 g/m²) and 9.66% (72.13 g/m²), respectively. A similarity analysis showed that there were regional differences in the algal communities, with three distinct groups.

• Food Science of Animal Resources
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• v.44 no.1
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• pp.146-164
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• 2024

Owing to the residual toxicity and adverse health effects of chemical preservatives, there is an increasing demand for using natural preservatives in food. Although many natural extracts have been evaluated, research on their antibacterial effects remains insufficient. Therefore, this study aimed to explore the possibility of developing Psidium guajava, Ecklonia cava, and Paeonia japonica (Makino) Miyabe & Takeda extracts as natural food preservatives. Further, the effect of mixing these extracts on microbial growth and quality was evaluated during the refrigeration of sausages. Optimal mixing ratios were determined based on the minimum inhibitory and bactericidal concentrations of each mixed extract against the Listeria monocytogenes, Salmonella spp. and Escherichia coli. D-optimal mixing design optimization tool was further used to obtain an optimum mixing ratio of Formulation 1 (F1). The antibacterial activity of F1 increased with increasing concentration, with similar activities at 0.5% and 1%. The sausages with synthetic or natural preservatives showed significantly lower lipid oxidation than those of the control and grapefruit extract-treated sausages after 4 wk of refrigeration. Total plate counts were observed only in the control and treatment groups stored for 3 wk, and no significant effect of ascorbic acid was observed. Compared to the other samples, sausages with added natural extracts showed the highest overall acceptability scores initially and after 4 wk. Therefore, similar amounts of grapefruit seed and natural extracts had the same effect on microbiological analysis and lipid rancidity during sausage storage. Hence, this mixture can serve as a potential natural preservative in meat products.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.57 no.1
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• pp.79-87
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• 2024

We seasonally examined marine macroalgal community structures in the subtidal zones at Gapado Island, Jeju, Korea, from February 2013 to November 2019. A total of 164 macroalgal species were identified, including 15 green, 40 brown, and 109 red algae. Species richness ranged from 54-106 species, with the maximum observed in 2013 and the minimum observed in 2015. Cladophora wrightiana var. minor, Ecklonia cava, Amphiroa anceps, Corallina aberrans, Corallina crassisima, Synarthrophyton chejuense, Sonderophycus capensis and Plocamium telfairiae occurred in all seasons. The average annual seaweed biomass was 1,258.22 g wet wt./m², ranging from 917.51 g/m² in 2017 to 1,551.95 g/m² in 2014. E. cava was the most dominant species, accounting for 46.57% of the total seaweed biomass. The subdominant species were P. telfairiae and A. anceps, comprising 8.64% (108.75 g/m²) and 6.65% (83.61 g/m²) of the total biomass, respectively. The vertical distribution of subtidal seaweeds were represented by E. cava and P. telfairiae at 5-20 m, A. anceps at 10-20 m, C. aberrans and C. crassisima at 5 m and C. wrightiana var. minor at 10 m. Cluster analysis revealed three distinct groups: group A (2014-2018), group B (2019) and group C (2013), indicating significant differences in the annual seaweed community.

• Journal of Life Science
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• v.23 no.9
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• pp.1155-1162
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• 2013

Estrogen like activities were evaluated using ethanol and hot water extracts of gongjindan (GJD) and 3 types of brown algae by an in vitro detection system. Laminaria japonica and Undaria pinnatifida represented statistically significant (p<0.001) estrogen like activities, while GJD and Ecklonia stolonifera did not. Furthermore, activities of hot water extracts ($500{\mu}g/ml$) of Laminaria japonica and three mixture (Ecklonia stolonifera : Undaria pinnatifida : Laminaria japonica, 1: 1: 1) were stronger than that of $10^{-7}M$ $17{\beta}$-estradiol. These results suggest that Laminaria japonica contain estrogen like compounds. Based on these results, the prepared seaweed GJD were used for animal experiments about the effects on inhibition of platelet aggregation and serum lipid levels in ovariectomized rats. 9-week Old female SD-rats were randomly assigned to 3 groups as sham-operated rats, ovariectomized rats and ovariectomized rats that were treated with GJD. The rats were placed on prescribed diets for 5 weeks following ovariectomy. Total cholesterol and triglyceride contents on serum decreased in the SHAM group compared to the OVX-CON group. 5 weeks feeding of GJD resulted in significant lowering of triglyceride and a decreasing tendency of total cholesterol level. The level of HDL-cholesterol on serum increased significantly by feeding diets containing the GJD. The ability of platelet aggregation of group treated with GJD was less than that of the OVX-CON group. These results suggest that the beneficial effects of seaweed gongjindan may be used to improve menopausal syndrome.

• Korean Journal of Environment and Ecology
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• v.36 no.6
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• pp.627-638
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• 2022

This study was conducted at a village fishing farm on 4 peaks on the main island of Jeju Island and 2 peaks on an inhabited island to compare the distribution characteristics of seaweeds along the coast of Jeju Island from May to December 2018. A total of 101 species of seaweeds were surveyed, including 13 species (12.9%) of green algae, 24 species (23.8%) of Phaeophyta, and 64 species (63.4%) of Rhodophyta. The largest number of seaweeds appeared in May and the fewest in October, showing typical features of a temperate sea area. The number of seaweed species that appeared was 66 and 65 species at the water depths of 5 m and 8 m, respectively, and the largest was 74 species at 12 m. The number of seaweeds that appeared by area was the largest at 66 species on Udo Island, an eastern island near Jeju Island, and the lowest at 27 species in Pyoseon-ri, an eastern part of Jeju Island. The important values of emerging species were high in the order of, Ecklonia cavaand Corallina crassissima at 21.1% and 20.3%, respectively, Corallina aberransat 9.2%, Amphora ephedraeaat 6.2%, and Sargassum macrocarpumat 4.4%. Among seaweeds, an average of 11.2 species of coralline algae appeared, and the mean importance value was 32.6% in the sear area. The lowest importance value was 14.7% on Udo Island, and the highest was 41.0% in Pyoseon-ri. The mean ecological evaluation index (EEI) of seaweed colonies ranged from 2.1 to 10. It was the lowest at the water depth of 12 m in Pyoseon-ri in May and June and was 7.3 or higher in other areas, indicating good condition. This study rated the standardized ecological grade I for the water depth of 12 m on Udo Island and grade II for the water depths of 5 m and 8 m in Sagye-ri and on Chujado Island. Grade III was the water depth of 5 m and 12 m in Pyoseon-ri and Guideok 2-ri and the water depth of 5 m and 8 m in Pyeongdae-ri, and grade IV was the water depth of 8 m in Guideok 2-ri.

• Korean Journal of Food Science and Technology
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• v.5 no.2
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• pp.101-107
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• 1973

1) For the purpose of preparation of food and fodder yeasts from nonedible seaweed, two suitable Candida yeasts have been isolated from seaweed compost. 2) They had the ability of fermenting galactose, sucrose and glucose, and could not ferment maltose and mannit, but could assimilate mannit. 3) NaCl concentration from 1 to 2% had no remarkable effect on growth of yeast and the optimum pH was $4{\sim}5$. 4) In the acid hydrolyzate of brown seaweed (Ecklonia cava Kjellman, Sargassum fulvellum AGARDH) an amorphous deposit was produced during storage after neutralization of media and its removal always delayed yeast growth, but addition of $(NH_4)_2SO_4$ and $NaH_2PO_4$ to media could increase the assimilation of reducing sugar and yeast yield. 5) $Co^{60}$ gamma ray irradiation (dose rate : 1 Mrad/hr, BNL shipboard irradiator) of seaweed had not so much effect on the hydrolysis of carbohydrates and nitrogen compounds in seaweed but could increase the yeast production from seaweed hydrolyzate. 6) The yeast yield was $7{\sim}8$ g of dry yeast per 100 g of seaweed by cultivation with jar fermentor.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2004.11a
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• pp.23-25
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• 2004

This study was conducted to investigate the effects of dietary supplementation of Ecklonia cava kjellman(ECK) and crude lectin extracted from ECK (CLEEC) on performances and immune responses in broiler chicks. A total of two hundreds thirty four 1 day old male broiler chicks (Ross) were fed corn-soy based diets containing 0 % (with or without vaccination and Salmonella challenge), 1.0 % ECK, 0.05 %, 0.1 % and 0.3 % CLEEC for 38 days and vaccinated against inactivated ND-IB combined oil vaccine on the fourth day. After S. gallinarum challenge. mortality was measured daily. The spleens of birds were removed for RNA extraction and reverse transcription polymerase chain reaction (RT-PCR) with primer sets for IFN-ν, IL-2, IL-6 and ${\beta}$-actin were performed with RNA samples. At the 28th day, pancreas weights were heavier 0.3 % CLEEC than 1.0 % ECK group. At the 21st day after ND-IB oil vaccine injection, dietary supplementation of ECK and CLEEC tended to increase or significantly (P<0.05) improved ND or IB titer compared to the positive control. Mortality was significantly (P<0.05) decreased by dietary CLEEC treatments. Chicken splenic IFN-ν, IL-2, and IL-6 cytokines mRNA expressions were enhanced by challenge with S, gallinarum. Dietary treatments did not affect mRNA expression of IFN-ν. However, IL-2 and IL-6 expressions in Salmonella challenged birds that fed the 1.0 % ECK or 0.05 % CLEEC groups were enhanced (P<0.05) compare to the positive control. The results demonstrated that dietary ECK and CLEEC enhanced humoral and cellular immunity and therefore. it can be concluded that dietary supplementation of ECK and CLEEC can be used as a feed additive for enhancement of immunocompetence without any adverse effects in broiler chicks.